Selective and Sensitive Dopamine Detection Using the Pictet-Spengler Reaction for Surface-Enhanced Raman Scattering

Dopamine (DA) presents significant challenges for direct quantification using surface-enhanced Raman scattering (SERS) due to its relatively small Raman cross section and the complexity of biological fluids. To address these limitations, this study introduces a novel approach combining the Pictet-Spengler (P-S) reaction with SERS for selective and sensitive DA detection. This method involves the preparation of aldehyde-modified layered double hydroxide, which effectively anchors DA molecules via the P-S reaction. This reaction is highly specific to DA, significantly enhancing the detection selectivity by overcoming interference from other molecules. Silver nanoparticles loaded with 4-mercaptophenylboronic acid are used as SERS probes for the indirect quantification of DA. The DA detection method demonstrated stability, achieving a linear response across a concentration range of 10^-5-10^-10 mol·L^-1, with a minimum detection limit of 9.91 × 10^-12 mol·L^-1 (S/N = 3). The method also exhibited excellent performance in detecting DA in complex environments, such as simulated urine and cerebrospinal fluid samples, highlighting its potential application in diagnosing and monitoring neurological disorders.